In general, an air cylinder apparatus, in which an air cylinder being driven by pressurized air is integrally assembled with an electromagnetic valve, a circuit board, or the like for controlling the air cylinder, is hitherto known as, for example, disclosed in the following patent document 1, patent document 2, and so forth. These air cylinder apparatuses are used, for example, as welding guns for performing a spot-welding operation for automobile parts and so forth, actuators for performing a clamping operation, conveying operation, picking operation, or the like for parts in an automated assembling line for products, and so forth. The air cylinder apparatus is required to be small-sized, light-weighted, and air piping, transmission wires for transmitting drive power force, control signals, or the like in the air cylinder apparatus are required to be disposed in a manner so as not to disturb the work.
However, in the hitherto known air cylinder apparatus, the electromagnetic valve is attached on a side surface of the air cylinder and the air piping that connects the electromagnetic valve and a pressure chamber in an inside of the air cylinder is disposed in a manner so as to pass through an outside of the air cylinder. Thereby, depending on an intended purpose of the air cylinder apparatus, the electromagnetic valve, the air piping, or the like sometimes disturbs the work. In addition, there sometimes has also been a case that the electromagnetic valve, the air piping, or the like disturbs the work in a case that the air cylinder apparatus is required to be more small-sized.    Patent Document 1: Japanese Unexamined Patent Application Publication No. 2002-224846    Patent Document 2: Japanese Unexamined Patent Application Publication No. 2002-282796